The size, the power of the bass, and the ability to put luggage on top!! It's also removable! If you want reliable bass, this is it!!

COMP RT A model with a built-in amplifier and a downward facing woofer box.
KICKER's power-down fire enclosure is equipped with a passive refrex subwoofer and KICKER COMP RT, allowing you to enjoy more powerful bass than a tune-up woofer without requiring much space or an external amplifier.
The amplifier can be installed in a layout, and the connector type makes loading and unloading easy.